Residues of C-4n-nonylphenol in mosquitofish (Gambusia holbrooki) oocytes and embryos during dietary exposure of mature females to this xenohormone     

Rmi Thibaut  Gilles Monod  Jean-Pierre Cravedi 《Marine environmental research》2002,54(3-5)

In order to assess in fish the maternal transfer of alkylphenolic compounds to the progeny, the identification and quantification of the labelled compounds present in oocytes and embryos was conducted after dietary exposure of mature female mosquitofish to ¹⁴C-4n-nonylphenol during vitellogenesis and embryogenesis respectively. Radioactivity found in bile and liver extracts accounted for 0.9–0.6 and 0.2–0.1% of ingested radioactivity for females exposed during vitellogenesis and embryogenesis respectively. The amount of extractable radioactivity present in oocytes and embryos was 0.19 and 0.07% of the ingested dose respectively. The radio-HPLC profiles obtained from bile, liver, oocyte and embryo extracts were similar. They showed the presence of 4n-NP-glucuronide as the major metabolite and traces of unchanged 4n-NP. The other metabolites corresponded to 8-hydroxynonylphenol, 9-(4-hydroxyphenyl)-nonanoic acid and para-hydroxybenzoic acid which is the final product of the alkyl chain oxidation. Our results indicate that exposure of ovoviviparous female fish to 4-NP during vitellogenesis and embryogenesis leads to the contamination of the progeny by 4-NP and its metabolites.  相似文献   

Contrasting trace element geochemistry in two American and French salt marshes     

B. Velde  T. Church  A. Bauer 《Marine Chemistry》2003,83(3-4):131

Trace metals were analyzed in the bulk fine phase of two contrasting salt marsh cores on the North Atlantic east (Baie de l'Aiguillon, LaRochelle, France) and west (Lewes, DE, USA) coasts. The purpose is to gauge how the different clay mineral sources and surface sedimentary diagenetic conditions affect the respective trace element geochemistries. It has been established that there is considerably more clay mineral diagenesis at the zone of redox transition in the Delaware core than in the l'Aiguillon core. The Delaware core shows unweathered glacial sedimentary material directly deposited from the continental shelf whereas the l'Aiguillon core is formed from soil clays deposited after river and estuarine transport. Although there is strong Mn redox depletion in the Delaware salt marsh core, and enrichment in the French one at l'Aiguillon, transition elements seem to follow iron content in both cores. The trace pollutant elements Pb, Sn and Zn show pronounced depth profiles in both North Atlantic cores. The Pb, Sn and Zn appear to be carried by clay sources into the French marshes, while appearing to be largely deposited by atmospheric processes as well into the Delaware marsh.Upon deposition, the Zn appears to become decoupled from lead, which is probably more strongly fixed on clays. The Sn seems to be both air transported, and carried as well on non-clay phases contaminated by industrial organo-tins, including antifouling bottom paints. Copper while uniformly enriched in France, probably from use in regional vineyards, appears enriched only near the top at Delaware, suggesting diagenetic recycling in the more abundant peat in the surface. The Cs and Li appear to be tracers for specific soil-derived clay sources in the French core source materials. These observations suggest that clay is a very important carrier in fixing trace elements for historical records as salt marsh sediments.  相似文献   

Climate simulations for 1880–2003 with GISS modelE     

J. Hansen  M. Sato  R. Ruedy  P. Kharecha  A. Lacis  R. Miller  L. Nazarenko  K. Lo  G. A. Schmidt  G. Russell  I. Aleinov  S. Bauer  E. Baum  B. Cairns  V. Canuto  M. Chandler  Y. Cheng  A. Cohen  A. Del Genio  G. Faluvegi  E. Fleming  A. Friend  T. Hall  C. Jackman  J. Jonas  M. Kelley  N. Y. Kiang  D. Koch  G. Labow  J. Lerner  S. Menon  T. Novakov  V. Oinas  Ja. Perlwitz  Ju. Perlwitz  D. Rind  A. Romanou  R. Schmunk  D. Shindell  P. Stone  S. Sun  D. Streets  N. Tausnev  D. Thresher  N. Unger  M. Yao  S. Zhang 《Climate Dynamics》2007,29(7-8):661-696

We carry out climate simulations for 1880–2003 with GISS modelE driven by ten measured or estimated climate forcings. An ensemble of climate model runs is carried out for each forcing acting individually and for all forcing mechanisms acting together. We compare side-by-side simulated climate change for each forcing, all forcings, observations, unforced variability among model ensemble members, and, if available, observed variability. Discrepancies between observations and simulations with all forcings are due to model deficiencies, inaccurate or incomplete forcings, and imperfect observations. Although there are notable discrepancies between model and observations, the fidelity is sufficient to encourage use of the model for simulations of future climate change. By using a fixed well-documented model and accurately defining the 1880–2003 forcings, we aim to provide a benchmark against which the effect of improvements in the model, climate forcings, and observations can be tested. Principal model deficiencies include unrealistically weak tropical El Nino-like variability and a poor distribution of sea ice, with too much sea ice in the Northern Hemisphere and too little in the Southern Hemisphere. Greatest uncertainties in the forcings are the temporal and spatial variations of anthropogenic aerosols and their indirect effects on clouds. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

High-end aerial digital cameras and their impact on the automation and quality of the production workflow     

Nicolas Paparoditis  Jean-Philippe Souchon  Gilles Martinoty  Marc Pierrot-Deseilligny 《ISPRS Journal of Photogrammetry and Remote Sensing》2006,60(6):400

The IGN digital camera project was established in the early 1990s. The first research surveys were carried out in 1996 and the digital camera was first used in production in 2000. In 2004 approximately 10 French departments (accounting for 10% of the territory) were covered with a four-head camera system and since summer 2005 all IGN imagery has been acquired digitally. Nevertheless the camera system is still evolving, with tests on new geometric configurations being continuously undertaken. The progressive integration of the system in IGN production workflows has allowed IGN to keep the system evolving in accordance with production needs. Remaining problems are due to specific camera characteristics such as CCD format, the optical quality of off-the-shelf lenses, and because some production tools are ill-adapted to digital images with a large dynamic range. However, when considering the pros and cons of integrating these images into production lines, the disadvantages are largely balanced by the numerous benefits this technology offers.  相似文献   

Influence of observed and RCM-simulated precipitation on the water discharge over the Sirba basin, Burkina Faso/Niger     

Christophe Messager  Hubert Gallée  Olivier Brasseur  Bernard Cappelaere  Christophe Peugeot  Luc Séguis  Michel Vauclin  Romain Ramel  Gilles Grasseau  Laurent Léger  Denis Girou 《Climate Dynamics》2006,27(2-3):199-214

The forcing of a hydrologic model (ABC) by both observed and simulated precipitation from a regional climate model (MAR) has been performed over the Sirba watershed (39,000 km²) located in the Sahelian region. Two aspects have been more specifically examined: the spatial and temporal representations of precipitation. The comparison between simulated and observed discharges—using observed rainfall datasets as forcing of the hydrologic model—has shown that the representation of daily precipitation (which is mainly convective in the Sahelian region) was not sufficiently accurate to correctly simulate the hydrologic response of the watershed. Since this response drives the soil water budget and consequently the amount of evaporation in forthcoming coupling experiments, it is thus necessary to develop more realistic infra-daily precipitation associated with convective events. A new temporal disaggregation scheme has been then developed. Considering observed as well as simulated precipitation fields, this method has significantly improved the simulated discharge at the catchment outlet. The major role played by the temporal component compared to spatial component of the precipitation has been then underlined. In addition, the present study shows the unsuitability of the simulated precipitation from the RCM to directly force a hydrologic model at infra daily timescale even if the cumulative amount and the main features of the precipitation seasonal cycle are well simulated.  相似文献   

Remote Sensing Observations of Effects of Mountain Blocking on Travelling Gravity-Shear Waves and Associated Clouds     

Roger F. Reinking  A. Shelby Frisch  Brad W. Orr  David L. Korn  Luc R. Bissonnette  Gilles Roy 《Boundary-Layer Meteorology》2003,109(3):255-284

Trapped Kelvin–Helmholtz (K–H) waves and vortices were monitored as they were generated immediately upwind of a mountain and driven into the barrier by a low-level jet. A stratus cloud visually revealed the embedded, propagating, gravity-shear waves. Interactions of the waves with the mountain were deciphered using remote sensing measurements of the structure, motions, and microphysics within the cloud and conceptual models based on existing theories. The observations show that the mountain acted as a dam to the flow that was primed for, but did not spontaneously induce, the waves. In response to the blocking, the waves spatially developed a pattern of formation, amplification, and breakdown between the upstream flow and the barrier, and altered the associated clouds in the process. Notably, radar signatures of velocity variance depicted organized, intertwined ribbons of relatively large vorticity within the wave layer. These provided measured evidence of the vortex sheet and streamwise vortex tubes predicted by advanced K–Hinstability theory, the three-dimensional version of Scorer's `stripe', the layer of rotational fluid between opposed flows that led to the wave generation. A theory of resonant interaction of wave trains, but with blocking imposed, appears to explain the internal structure of the pile-up of the flow and wave amplification approaching the barrier. Evolution of the supporting atmospheric thermal structure and introduction of a boundary-layer flow reversal follow a current model of blocking, although some features may have developed more directly from wave-driven mixing. The remote sensors also measured the influence of the waves on the cloud liquid water, including a cumulative enlargement of droplets as they were carried through a series of waves.  相似文献   

ISAES IX, Potsdam, Germany, September 8-12, 2003     

Wilfried Bauer 《Gondwana Research》2004,7(2):636-637

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Mono Lake or Laschamp geomagnetic event recorded from lava flows in Amsterdam Island (southeastern Indian Ocean)   总被引：1，自引：0，他引：1  

Claire Carvallo  Pierre Camps  Gilles Ruffet  Bernard Henry  T. Poidras 《Geophysical Journal International》2003,154(3):767-782

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La stratigraphie oligo-miocène et la surface d'érosion messinienne en mer Noire,stratigraphie sismique haute résolution     

Hervé Gillet  Gilles Lericolais  Jean-Pierre Rehault  Corneliu Dinu 《Comptes Rendus Geoscience》2003,335(12):907-916

The stratigraphy of the Black Sea western margin is revisited through seismic data acquired during two French-Romanian surveys. These data are calibrated by industrial and DSDP drillings; they display several major discontinuities regarded as Tertiary erosional surfaces. The major seismic discontinuity underlines the base of Miocene formations and corresponds to a composite surface including at least three erosional phases ranging from Oligocene to Pontian times. Moreover, a Messinian erosional surface is clearly identified. This is in agreement with the Hsü's proposition [Palaeogeogr. Palaeoclimatol. Palaeoecol. 29 (1979) 75–93] suggesting a Messinian sea-level drop of Black Sea related to the Messinian Salinity Crisis described in the Mediterranean Sea. To cite this article: H. Gillet et al., C. R. Geoscience 335 (2003).  相似文献   

Peatland Initiation During the Holocene in Continental Western Canada   总被引：4，自引：0，他引：4  

Linda A. Halsey  Dale H. Vitt  Ilka E. Bauer 《Climatic change》1998,40(2):315-342

Today, the southern limit of peatlands in continental western Canada is largely limited by thermal seasonal aridity, although physiographic parameters of substrate texture, topography, and salinity also exsert important controls on the presence and absence of peatlands. Factors that control peatland distribution today also operated in the past, thus the initiation of peatlands during the Holocene was mainly limited by aridity and physiography. Calibrated radiocarbon dates of basal peat deposits from 90 locations across continental western Canada indicate that peat formation began approximately 8,000 to 9,000 years BP in nucleation zones along the upper elevations of the Montane region of Alberta and in northern Alberta uplands after an initial deglacial lag. Predictions of maximum early Holocene summer insolation by climate simulations provide a mechanism for limiting peatland establishment during the early Holocene. From 6,000 to 8,000 years ago, peat formation in continental western Canada expanded eastwards into Manitoba responding to decreases in summer insolation. Peatland expansion during the early Holocene was more extensive in Alberta than in Manitoba in response to a southwesterly shift in the Arctic front. The displacement of the Arctic front allowed for more frequent incursions of moist Pacific air into Alberta while limiting it in Manitoba. After 6,000 years BP, the trend of southeasterly peatland expansion continued. Peatlands are youngest in the southern Boreal Forest and Aspen Parkland Region as well as in the lower elevations of the Peace-Wapiti River drainage basin, forming over the last 3,000 to 4,000 years. Peatlands are also young in the lower elevations of the Hudson Bay Lowlands where peat initiation has been limited by timing of emergence from glacial rebound. The spatial and temporal distribution of peatland initiation during the Holocene is verified by existing pollen records and corroborates some simulated climate models.  相似文献